<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>
  
  <script>
    DrawingTools =(function(){
                //公共方法
                var getDom=function(id){return document.getElementById(id)};
            var isNull=function(s){return s==undefined||typeof(s)=='undefined'||s==null||s=='null'||s==''||s.length<1};
            var hideDefRM=function(){document.oncontextmenu=function(){return false}};//屏蔽浏览器默认鼠标事件
            /**绘图容器*/
            var cbtCanvas;
            /**绘图对象*/
            var cxt;
            /**绘制的图形列表*/
            var shapes=new Array();

            var graphkind={'cursor':0,'pen':1,'line':2,'trian':3,'rect':4,'poly':5,'circle':6,'arrow':21,'parallel':41,'trapezoid':42};
            //背景图片绘制配置
            var bgPictureConfig={
                pic:null,//背景图片地址或路径
                repaint:true,//是否作为永久背景图，每次清除时会进行重绘
            };
            //加载并绘制图片(src:图片路径或地址),默认重绘背景图
            var loadPicture=function(src){
                if(isNull(bgPictureConfig.repaint)||bgPictureConfig.repaint){bgPictureConfig.pic=src}
                var img = new Image();
                img.onload = function(){cxt.drawImage(img,0,0)}
                img.src =src;
            }

            //绘图基础配置
            var paintConfig={lineWidth:1,//线条宽度，默认1
                strokeStyle:'red',//画笔颜色，默认红色
                fillStyle:'red',//填充色
                lineJoin:"round",//线条交角样式，默认圆角
                lineCap:"round",//线条结束样式，默认圆角
            };
            //重新载入绘制样式
            var resetStyle=function(){
                cxt.strokeStyle=paintConfig.strokeStyle;
                cxt.lineWidth=paintConfig.lineWidth;
                cxt.lineJoin=paintConfig.lineJoin;
                cxt.lineCap=paintConfig.lineCap;
                cxt.fillStyle=paintConfig.fillStyle;
            }

            //鼠标图形
            var cursors=['crosshair','pointer'];
            /** 切换鼠标样式*/
            var switchCorser=function(b){
                cbtCanvas.style.cursor=((isNull(b)?isDrawing():b)?cursors[0]:cursors[1]);
            }
            //操作控制变量组
            var ctrlConfig={
                kind:0,//当前绘画分类
                isPainting:false,//是否开始绘制
                startPoint:null,//起始点
                cuGraph:null,//当前绘制的图像
                cuPoint:null,//当前临时坐标点，确定一个坐标点后重新构建
                cuAngle:null,//当前箭头角度
                vertex:[],//坐标点
            }
            /**获取当前坐标点*/
            var getCuPoint=function(i){
                return ctrlConfig.cuPoint[i];
            }
            /**设置当前坐标点*/
            var setCuPoint=function(p,i){
                return ctrlConfig.cuPoint[i]=p;
            }
            /**设置当前临时坐标点值*/
            var setCuPointXY=function(x,y,i){
                if(isNull(ctrlConfig.cuPoint)){
                    var arr=new Array();
                    arr[i]=new Point(x,y);
                    ctrlConfig.cuPoint=arr;
                }else if(isNull(ctrlConfig.cuPoint[i])){
                    setCuPoint(new Point(x,y),i);
                }else{
                    ctrlConfig.cuPoint[i].setXY(x,y);
                }
                return getCuPoint(i);
            }

            /**是否正在绘制*/
            var isDrawing=function (){
                return ctrlConfig.isPainting;
            }
            /**开始绘制状态*/
            var beginDrawing=function(){
                ctrlConfig.isPainting=true;
            }
            /**结束绘制状态*/
            var stopDrawing=function(){
                ctrlConfig.isPainting=false;
            }
            /**是否有开始坐标点*/
            var hasStartPoint=function(){
                return !isNull(ctrlConfig.startPoint);
            }
            /**设置当前绘制的图形*/
            var setCuGraph=function(g){
                ctrlConfig.cuGraph=g;
            }
            /**获取当前绘制的图形*/
            var getCuGraph=function(){
                return ctrlConfig.cuGraph;
            }
            /**设置开始坐标点（线条的起始点，三角形的顶点，圆形的圆心，四边形的左上角或右下角，多边形的起始点）*/
            var setStartPoint=function(p){
                ctrlConfig.startPoint=p;
            }
            /**获取开始坐标点*/
            var getStartPoint=function(){
                return ctrlConfig.startPoint;
            }

            /**清空全部*/
            var clearAll=function(){
                cxt.clearRect(0,0,cbtCanvas.width,cbtCanvas.height);
            }
            /**重绘*/
            var repaint=function(){
                clearAll();
                /*
                if(bgPictureConfig.repaint){
                    loadPicture(bgPictureConfig.pic);
                }*/
            }

            /**点（坐标,绘图的基本要素,包含x,y坐标）*/
            var Point=(function(x1,y1){
                var x=x1,y=y1;
                return{
                    set:function(p){
                        x=p.x,y=p.y;
                    },
                    setXY:function(x2,y2){
                        x=x2;y=y2;
                    },
                    setX:function(x3){
                        x=x3;
                    },
                    setY:function(y3){
                        y=y3;
                    },
                    getX:function(){
                        return x;
                    },
                    getY:function(){
                        return y;
                    }
                }
            });
            /**多角形（三角形、矩形、多边形），由多个点组成*/
            var Poly=(function(ps1){
                var ps=isNull(ps1)?new Array():ps1;
                var size=ps.length;
                return{
                    set:function(ps2){
                        ps=ps2;
                    },
                    getSize:function(){
                        return size;
                    },
                    setPoint:function(p,i){
                        if(isNull(p)&&isNaN(i)){
                            return;
                        }
                        ps[i]=p;
                    },
                    setStart:function(p1){
                        if(isNull(ps)){
                            ps=new Array();
                            return ps.push(p1);
                        }else{
                            ps[0]=p1;
                        }
                    },
                    add:function(p){
                        if(isNull(ps)){
                            ps=new Array();
                        }
                        return ps.push(p);
                    },
                    pop:function(){
                        if(isNull(ps)){
                            return;
                        }
                        return ps.pop();
                    },
                    shift:function(){
                        if(isNull(ps)){
                            return;
                        }
                        return ps.shift;
                    },
                    get:function(){
                        if(isNull(ps)){
                            return null;
                        }
                        return ps;
                    },
                    draw:function(){
                        cxt.beginPath();
                        for(i in ps){
                            if(i==0){
                                cxt.moveTo(ps[i].getX(),ps[i].getY());
                            }else{
                                cxt.lineTo(ps[i].getX(),ps[i].getY());
                            }
                        }
                        cxt.closePath();
                        cxt.stroke();
                    }
                }
            });
            /*线条(由两个点组成，包含方向)*/
            var Line=(function(p1,p2,al){
                var start=p1,end=p2,angle=al;

                var drawLine=function(){
                    cxt.beginPath();
                    cxt.moveTo(p1.getX(),p1.getY());
                    cxt.lineTo(p2.getX(),p2.getY());
                    cxt.stroke();
                }
                //画箭头
                var drawArrow=function() {
                    var vertex =ctrlConfig.vertex;
                    var x1=p1.getX(),y1=p1.getY(),x2=p2.getX(),y2=p2.getY();
                    var el=50,al=15;
                    //计算箭头底边两个点（开始点，结束点，两边角度，箭头角度）
                    vertex[0] = x1,vertex[1] = y1, vertex[6] = x2,vertex[7] = y2;
                    //计算起点坐标与X轴之间的夹角角度值
                    var angle = Math.atan2(y2 - y1, x2 - x1) / Math.PI * 180;
                    var x = x2 - x1,y = y2 - y1,length = Math.sqrt(Math.pow(x, 2) + Math.pow(y, 2));
                    if (length < 250) {
                        el/=2,al/2;
                    }else if(length<500){
                        el*=length/500,al*=length/500;
                    }
                    vertex[8] = x2 - el * Math.cos(Math.PI / 180 * (angle + al));
                    vertex[9] = y2- el * Math.sin(Math.PI / 180 * (angle + al));
                    vertex[4] = x2- el* Math.cos(Math.PI / 180 * (angle - al));
                    vertex[5] = y2 - el * Math.sin(Math.PI / 180 * (angle - al));
                    //获取另外两个顶点坐标
                    x=(vertex[4]+vertex[8])/2,y=(vertex[5]+vertex[9])/2;
                    vertex[2] = (vertex[4] + x) / 2;
                    vertex[3] = (vertex[5] + y) / 2;
                    vertex[10] = (vertex[8] +x) / 2;
                    vertex[11] = (vertex[9] +y) / 2;
                    //计算完成,开始绘制
                    cxt.beginPath();
                    cxt.moveTo(vertex[0], vertex[1]);
                    cxt.lineTo(vertex[2], vertex[3]);
                    cxt.lineTo(vertex[4], vertex[5]);
                    cxt.lineTo(vertex[6], vertex[7]);
                    cxt.lineTo(vertex[8], vertex[9]);
                    cxt.lineTo(vertex[10], vertex[11]);
                    cxt.closePath();
                    cxt.fill();
                    cxt.stroke();
                }
                return{
                    setStart:function(s){
                        start=s;
                    },
                    setEnd:function(e){
                        end=e;
                    },
                    getStart:function(){
                        return start;
                    },
                    getEnd:function(){
                        return end;
                    },
                    draw:function(){
                        if(angle){
                            drawArrow();
                        }else{
                            drawLine();
                        }
                    }
                }
            });
            /**圆形(包含圆心点和半径)*/
            var Circle=(function(arr){
                //包含起始点（圆心）和结束点,以及圆半径
                var startPoint=arr.start,endPoint=arr.end,radius=arr.radius;
                /*绘制圆*/
                var drawCircle=function(){
                    cxt.beginPath();
                    var x=startPoint.getX();
                    var y=startPoint.getY();
                    if(isNull(radius)){
                        radius=calculateRadius(startPoint,endPoint);
                    }
                    //x,y,半径,开始点,结束点,顺时针/逆时针
                    cxt.arc(x,y,radius,0,Math.PI*2,false); // 绘制圆
                    cxt.stroke();
                }
                //计算圆半径
                var calculateRadius=function(p1,p2){
                    var width=p2.getX()-p1.getX();
                    var height=p2.getY()-p1.getY();
                    //如果是负数
                    if(width<0||height<0){
                        width=Math.abs(width);
                    }
                    //计算两点距离=平方根(width^2+height^2)
                    c=Math.sqrt(Math.pow(width,2)+Math.pow(height,2));
                    return c;
                }
                return{
                    set:function(params){
                        startPoint=params.start;
                        endPoint=params.end;
                        radius=params.radius;
                    },
                    setPoint:function(p1){
                        p=p1;
                    },
                    getPoint:function(){
                        return p;
                    },
                    setRadius:function(r1){
                        radius=r1;
                    },
                    getRadius:function(){
                        return radius;
                    },
                    calcRadius:calculateRadius,
                    //绘制
                    draw:drawCircle,
                }
            });
            /**绘制线条工具方法*/
            var drawLine=function(p){
                cxt.beginPath();
                cxt.moveTo(startPosition.getX(),startPosition.getY());
                cxt.lineTo(p.getX(),p.getY());
                cxt.stroke();
            }

            /**绘制三角形工具方法*/
            var drawTrian=function(ps){
                cxt.beginPath();
                var a=ps.get();
                cxt.moveTo(a[0].getX(),a[0].getY());
                cxt.lineTo(a[1].getX(),a[1].getY());
                cxt.lineTo(a[2].getX(),a[2].getY());
                cxt.closePath();
                cxt.stroke();
            }

            /**绘制矩形工具方法*/
            var drawRect=function(p2){
                var p=getStartPoint();
                var width=p.getX()-p2.getX();
                var height=p.getY()-p2.getY();
                cxt.beginPath();
                cxt.strokeRect(x,y,width,height);//绘制矩形
            }

            /*绘制多边形工具方法*/
            var drawpolygon=function(ps){
                if(ps.length>1){//保证只有两个坐标点才是矩形
                    cxt.beginPath();
                    var p=ctrlConfig.startPoint;
                    var x=p.getX();
                    var y=p.getY();
                    cxt.moveTo(x,y);
                    for(p1 in ps){
                        cxt.lineTo(p1.getX(),p1.getY());
                    }
                    cxt.stroke();
                }
            }

            /*绘制圆角矩形工具方法*/
            var  drawRoundedRect=function(x,y,width,height,radius){
                cxt.beginPath();
                cxt.moveTo(x,y+radius);
                cxt.lineTo(x,y+height-radius);
                cxt.quadraticCurveTo(x,y+height,x+radius,y+height);
                cxt.lineTo(x+width-radius,y+height);
                cxt.quadraticCurveTo(x+width,y+height,x+width,y+height-radius);
                cxt.lineTo(x+width,y+radius);
                cxt.quadraticCurveTo(x+width,y,x+width-radius,y);
                cxt.lineTo(x+radius,y);
                cxt.quadraticCurveTo(x,y,x,y+radius);
                cxt.stroke();
            }
            /*绘制圆工具方法*/
            var drawCircle=function(c){
                var p=c.getPoint();//坐标点
                var x=p.getX();
                var y=p.getY();
                var r=c.getRadius();
                cxt.beginPath();
                //x,y,半径,开始点,结束点,顺时针/逆时针
                cxt.arc(x,y,r,0,Math.PI*2,false); // 绘制圆
                cxt.stroke();
            }
            //计算圆半径工具方法
            var calculateRadius=function(p1,p2){
                var width=p2.getX()-p1.getX();
                var height=p2.getY()-p1.getY();
                //如果是负数
                if(width<0||height<0){
                    width=Math.abs(width);
                }
                //计算两点距离=平方根(width^2+height^2)
                c=Math.sqrt(Math.pow(width,2)+Math.pow(height,2));
                return c;
            }

            //鼠标按键点击（首次点击确定开始坐标点，拖动鼠标不断进行图形重绘）
            var mouseDown = function(e){
                var btnNum = e.button;
                if(btnNum==0){
                    console.log("选择："+ctrlConfig.kind);
                    //设置起始点
                    switch(ctrlConfig.kind){
                        case graphkind.pen://画笔(不松开鼠标按键一直画)
                            beginDrawing();//开始绘制
                            cxt.beginPath();
                            cxt.moveTo(e.offsetX,e.offsetY);
                            break;
                        case graphkind.poly://多边形
                            var p=new Point(e.offsetX,e.offsetY);
                            if(isDrawing()){
                                getCuGraph().add(p);//添加到
                            }else{//第一次确定开始坐标
                                beginDrawing();//开始绘制
                                setStartPoint(p);
                                var poly=new Poly();
                                poly.add(p);
                                setCuGraph(poly);//设置当前绘制图形
                            }
                            break;
                        case graphkind.line://线条
                        case graphkind.arrow://方向
                        case graphkind.trian://三角形
                        case graphkind.rect://矩形
                        case graphkind.parallel://平行四边形
                        case graphkind.trapezoid://梯形
                            beginDrawing();//开始绘制
                            var p=new Point(e.offsetX,e.offsetY);
                            setStartPoint(p);
                            var poly=new Poly();
                            poly.add(p);
                            setCuGraph(poly);//设置当前绘制图形
                            break;
                        case graphkind.circle://圆
                            console.log("确定图形绘制开始坐标点："+e.offsetX+","+e.offsetY);//点击确定图形的开始坐标点
                            beginDrawing();//开始绘制
                            var p=new Point(e.offsetX,e.offsetY);
                            setStartPoint(p);
                            var circle= new Circle({'start':p});
                            setCuGraph(circle);
                            break;
                        case ctrlConfig.cursor: //手型鼠标
                        default://默认是手型鼠标，不允许绘制
                    }
                }else if(btnNum==2){
                    console.log("右键由于结束多边形绘制");
                    if(isDrawing()){
                        if(ctrlConfig.kind==graphkind.poly){
                            repaint();
                            getCuGraph().draw();
                            stopDrawing();//结束绘制
                        }
                    }
                }
                hideDefRM();//屏蔽浏览器默认事件
            }
            //鼠标移动（拖动，根据鼠标移动的位置不断重绘图形）
            var mouseMove = function(e){
                if(isDrawing()&&hasStartPoint()){//检查是否开始绘制，检查是否有开始坐标点
                    //画笔不需要重绘
                    if(ctrlConfig.kind>1){
                        repaint();//重绘
                    }
                    var p=setCuPointXY(e.offsetX,e.offsetY,0);//设置共享的临时坐标点，用于防止重复创建对象
                    switch(ctrlConfig.kind){
                        case graphkind.pen://画笔(一直画)
                            cxt.lineTo(e.offsetX,e.offsetY);
                            cxt.stroke();
                            break;
                        case graphkind.poly://多边形
                            var poly=getCuGraph(poly);
                            var size=poly.getSize();
                            poly.setPoint(p,(size-1));
                            poly.draw();
                            break;
                        case graphkind.line://线条
                            var line=new Line(getStartPoint(),p,false);
                            ctrlConfig.cuGraph=line;
                            line.draw();
                            break;
                        case graphkind.arrow://方向
                            var line=new Line(getStartPoint(),p,true);
                            ctrlConfig.cuGraph=line;
                            line.draw();
                            break;
                        case graphkind.trian://三角形
                            var lu=getStartPoint();
                            var x2=p.getX();
                            var x1=lu.getX();
                            //三角形左边的点坐标计算方法:(x1-(x2-x1),y2)
                            var x3=x1-(x2-x1);
                            var l=setCuPointXY(x3,p.getY(),1);//设置共享的临时坐标点，用于防止重复创建对象
                            var poly=getCuGraph();//获取当前图形
                            poly.set([lu,p,l]);
                            poly.draw();//即时绘制
                            break;
                        case graphkind.parallel://平行四边形
                            var lu=getStartPoint();
                            var x3=p.getX();
                            var x1=lu.getX();
                            //平行四边形两个未知坐标点计算方法:(x1-(x3-x1),y3),(x1+(x3-x1),y1)
                            var x2=x3+(x3-x1);
                            var x4=x1-(x3-x1);
                            var ld=setCuPointXY(x2,lu.getY(),1);//设置共享的临时坐标点，用于防止重复创建对象
                            var ru=setCuPointXY(x4,p.getY(),2);//设置共享的临时坐标点，用于防止重复创建对象
                            var poly=getCuGraph();//获取当前图形
                            poly.set([lu,ru,p,ld]);
                            poly.draw();//即时绘制
                            break;
                        case graphkind.trapezoid://梯形
                            var lu=getStartPoint();
                            var x3=p.getX();
                            var x1=lu.getX();
                            //梯形两个未知坐标点计算方法:(x3-(x3-x1)/2,y1),(x1-(x3-x1)/2,y3)
                            var x2=x3-(x3-x1)/2;
                            var x4=x1-(x3-x1)/2;
                            var ld=setCuPointXY(x2,lu.getY(),1);
                            var ru=setCuPointXY(x4,p.getY(),2);
                            var poly=getCuGraph();
                            poly.set([lu,ru,p,ld]);
                            poly.draw();
                            break;
                        case graphkind.rect://矩形
                            var lu=getStartPoint();
                            //矩形右上角和左上角坐标计算方法
                            var ld=setCuPointXY(lu.getX(),p.getY(),1);
                            var ru=setCuPointXY(p.getX(),lu.getY(),2);
                            var poly=getCuGraph();
                            poly.set([lu,ru,p,ld]);
                            poly.draw();
                            break;
                        case graphkind.circle://圆
                            var circle=getCuGraph();//获取当前图形
                            circle.set({'start':getStartPoint(),'end':p});
                            circle.draw();//即时绘制
                            break;
                    }
                }
            }
            //鼠标按键松开
            var mouseUp = function(e){
                if(isDrawing()){
                    //console.log("松开鼠标按键:"+e.offsetX+","+e.offsetY);
                    //画笔不需要重绘
                    if(ctrlConfig.kind>1){
                        repaint();
                        getCuGraph().draw();
                    }
                    if(ctrlConfig.kind!=graphkind.poly){//多边形绘制鼠标按键松开不结束绘制，多边形只有右键点击才能结束绘制
                        stopDrawing();//结束绘制
                    }
                }
            }

            //鼠标移出
            var mouseOut = function(e){
                console.log("鼠标移出绘制区域"+e.offsetX+","+e.offsetY);
                if(isDrawing()){
                    console.log("停止绘制");
                    if(ctrlConfig.kind>1){
                        repaint();
                        getCuGraph().draw();
                    }
                    stopDrawing();//停止绘制
                }
            }

            return{
                isNull:isNull,
                getDom:getDom,
                clear:function(){
                    stopDrawing();//停止绘制
                    repaint();
                },
                /**初始化*/
                init:function(params){
                    cbtCanvas=getDom(params.id);
                    //浏览器是否支持Canvas
                    if (cbtCanvas.getContext){
                        /**绘图对象*/
                        cxt=cbtCanvas.getContext("2d");
                        cbtCanvas.onmousedown = mouseDown;
                        cbtCanvas.onmouseup = mouseUp;
                        cbtCanvas.onmousemove = mouseMove;
                        cbtCanvas.onmouseout = mouseOut;
                        resetStyle();//载入样式
                        return true;
                    }else{
                        return false;
                    }
                },
                /**设置背景图片*/
                setBgPic:loadPicture,
                /**选择图形类型*/
                begin:function(k){
                    console.log("选择绘制图形："+k);
                    if(isNaN(k)){//如果不是数字，先转换为对应字符
                        ctrlConfig.kind=kind[k];
                    }else{
                        ctrlConfig.kind=k;
                    }
                    switchCorser(true);//切换鼠标样式
                },
                /*手型，并停止绘图*/
                hand:function(){
                    ctrlConfig.kind=0;
                    stopDrawing();//停止绘制
                    switchCorser(false);//切换鼠标样式
                }
            }
        })
        

  </script>
</body>
</html>